Maggie,
I couldn't find the exact sales price on Google. But just for reference, here is the link to an article about the 3DPrinting.Guru sale. http://domainshane.com/was-3dprintin...new-gtld-ever/

MessierGoal,
I think it will take some time before 3D Printing realizes even half of its potential. However, the 3D Printing market is widely expected to undergo double-digit growth over the next decade. So, as more 3D Printing startups become established each year, the demand for 3d printing domains correspondingly rises.
Although ipv6 may partially augment domain names once the Internet of Things takes off, I think that domain names will still be around in order to facilitate branding.